(a) Field of the Invention
The present invention relates to a lateral-flow deposition apparatus and a method of depositing film by using the apparatus.
(b) Description of the Related Art
A study for improving processes of apparatuses forming a high-quality film on a substrate in manufacturing semiconductor device has been conducted. Recently, an atomic layer deposition (ALD) has been proposed, which enables to form a thin film on a substrate by using surface reaction of two or more reaction gases that are sequentially supplied on a substrate at different time, and forms a thin film having a desired thickness by repeating this sequence. Since the film is formed by the surface reaction, according to this process, it is possible to achieve a film having a uniform thickness throughout the surface of the substrate, regardless of protrusions and depressions of the substrate, and form a film having excellent properties by reducing impurities contained in the film.
According to the atomic layer deposition, reaction gasses are sequentially supplied into a reactor in the order of a first reaction gas→an inert purge gas→a second reaction gas→an inert purge such that the reaction gases do not meet or react in a gas state in a reaction chamber, by using respective valves for each gas. This sequence is called ‘cycle’. Some of the reaction gases may be activated by plasma. Plasma atomic layer deposition that intermittently provides plasma in a reactor in synchronization with the sequential gas supply cycle has been disclosed in Korea Patent No. 273473 and U.S. Pat. No. 6,645,574.
In the atomic layer deposition apparatus used for atomic layer deposition, the gases flow fast and simply in parallel with a substrate in the reactor, so the lateral-flow atomic layer deposition reactor can lead to fast gas switching and minimize time for supplying sequentially the gases in a cycle As an example of the lateral-flow reactor, a reactor suitable for time-division gas supply atomic deposition and a method of depositing a thin film in the reactor has been disclosed in Korea Patent No. 624030 and U.S. Pat. No. 6,539,891. Further, a modified example has been disclosed in Korea Patent Application No. 2005-0038606 and U.S. patent application Ser. No. 11/429,533. According to this reactor, it is possible to perform plasma atomic layer deposition by supplying plasma power to an electrode, which supplies radio frequency (RF) power, in synchronization with the gas supply cycle.
Other examples of the lateral-flow atomic layer reactor have been disclosed in U.S. Pat. No. 5,711,811 and U.S. Pat. No. 6,562,140. In these inventions, the gas flow is maintained uniformly and close to laminar flow on a substrate by maintaining the gap between a surface where the substrate is placed and the surface opposite to the substrate in the reactors.
It is possible to form a completely uniform film, if atomic layers are formed layer by layer on the substrate; however, practically, non-uniformity of about 3% usually exists in the film formed by the atomic layer deposition, because of various reasons, particularly, because it is required to increase the deposition rate and productivity of the equipment by reducing the time for supplying gases in a cycle.
When the lateral-flow deposition reactor is used, the non-uniformity is generated usually in the gas flow direction. Further, the thickness of a thin film deposited in the lateral-flow deposition apparatus is larger usually at the gas inlet than the gas outlet, because the concentration of the gas is generally high at the gas inlet than at the gas outlet.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.